S.K. Sharma¹, S. Singh^*2, V.K. Chaudhary³, S. Kanhaiya¹ and S.K. Yadav¹

¹Department of Earth and Planetary Sciences, V. B. S. Purvanchal University, Jaunpur – 222003, Uttar Pradesh, India

²Department of Geology, Institute of Earth and Environmental Sciences, R.M.L. Avadh University, Ayodhya – 224001, Uttar Pradesh, India

³Department of Environmental Sciences, Instt. of Earth and Environmental Sciences, R.M.L. Avadh Univ., Ayodhya – 224001, Uttar Pradesh, India

(*Corresponding Author, E-mail: geosaurabh@gmail.com)

Abstract

The Ghaghara River, a major Himalayan tributary of the Ganga River, exhibits pronounced morphodynamical variability within its alluvial reaches of the Central Ganga Plain, Northern India. This study examines the morphodynamic behavior of the middle reaches of the Ghaghara River, specifically between Bahraich and Tanda, using remote sensing and field observations. Multi-temporal Landsat satellite imagery spanning 1975–2022, integrated with GIS-based analyses and detailed field observations were employed to quantify planform evolution, bankline shifting, and reach-wise morphodynamic responses. Quantitative bankline analysis indicates that left-bank migration ranges from 3.12 km to 4.22 km. In contrast, right-bank migration ranges from 3.37 km to 7.91 km, reflecting contrasting erosion and accretion patterns under changing hydrological conditions. The highest degree of channel instability is observed around the Rudauli–Goshainganj reach, where active meander expansion, cut-bank erosion, and point-bar accretion are dominant geomorphic processes. Sinuosity index range from 1.07 to 1.27 in Reach-A (Bahraich-Colonelganj), 1.10 to 1.24 in Reach-B (Colonelganj–Rudauli), 1.21 to 1.37 in Reach-C (Rudauli–Goshainganj), and 1.14 to 1.31 in Reach-D (Goshainganj-Tanda), with peak sinuosity generally recorded during the 1990–2020 period. Variations in channel length further indicate progressive meander development and localized cut-off events, particularly in Reach B (Colonelganj–Rudauli) and Reach C (Rudauli–Goshainganj).

Keywords: Ghaghara River, Channel migration, Channel sinuosity, Central Ganga Plain, India